The present invention relates to an improvement in a waterproof coupling structure of watchcase and, particularly, to an improvement in pins adapted to couple an outer rim which, in turn, couples a front cap to a rear cap to said rear cap to provide the desired waterproof effect and further to an improvement in the outer rim adapted for employment of said pin.
The pin of this type conventionally used to couple and hold the front cap and the rear cap of watchcase has had a thread thereon and been threaded through the outer rim into the rear cap having the correspondingly threaded hole. With such a watchcase coupling structure, the operation of assembling has been troublesome due to the particular step of threading-in operation and no external adjustment of the force with which the packing for waterproof effect is clamped has been possible.
To overcome these disadvantages, the present invention provides an improved coupling structure. A principal object of the present invention, therefore, is to improve the watchcase coupling structure and thereby to improve the efficiency in the operation of assembling the watchcase. A second object of the present invention is to couple the outer rim engaged with the front cap to the rear cap in such a manner that the force with which the packing principally for waterproof effect interposed between the front cap and the rear cap of watchcase may be easily adjusted. A third object of the present invention is to improve of configuration of the pin itself so that the operation of assembling the watchcase may be further facilitated. A fourth object of the present invention is to improve a configuration of the pin itself of a combination of configurations of the pin and the outer rim so as to prevent the pin from falling off once the watchcase has been assembled. The other objects of the present invention will be obvious from reading the following description in reference with preferred embodiments of the present invention.
The objects as mentioned hereinabove are achieved in accordance with the present invention by coupling the outer rim and the rear cap to establish coupling of the front cap and the rear cap utilizing an eccentric pin extending through the outer rim into the rear cap. The pin is configurated so that the periphery of pin head and the pin shank present a consecutive slant surface in order to facilitate the operation of mounting the pin through the outer rim into the rear cap. To prevent the pin from falling off once the pin has been mounted in the outer rim and the rear cap, the pin is provided with a member adapted to be interposed between the outer rim and the rear cap. As another measure to prevent the pin from falling off, said member mounted on the pin to be interposed between the outer rim and the rear cap is replaced by a rigid flange forced in unison with the pin and the outer rim is provided with a keyhole-shaped notch in conformity with such a particular arrangement of the pin, and the circular head of the pin is symmetrically cut away to present a pair of parallel surfaces so that the pin may be smoothly guided along said keyhole-shaped notch fron one end thereof. With the rear cap having a thin side wall, the pin having the circular flange to be used in combination with the outer rim having the keyhole-shaped notch has its shank end extended in the form of a notch and the pin insertion hole of the rear cap is formed as an opening extending through said side wall so that said shank end may be expanded to prevent the pin from falling off.